The urinary system plays an essential role in the body. The tract is composed of kidneys, ureters, the bladder, sphincter muscles and the urethra. The bladder is a hollow muscular organ that sits in the pelvis. Normal bladder function may easily be taken for granted, but when something goes wrong with this organ, a person can experience significant discomfort.
Bladder Function
The body's urinary system has several important functions. Among other tasks, it regulates fluid levels in the body and filters toxins and wastes from the blood steam for elimination in the urine. Urea is an example of a waste product that is processed by the urinary system. Urea is derived from the breakdown of dietary proteins, and it's a main constituent of urine. After the kidneys process the body's fluids and wastes, the excess substances move through the ureters and into the bladder, where the solution is stored. Once the bladder's capacity is reached, the body initiates the urine elimination process.
Bladder Filling
From the kidneys, urine travels through the ureters, two thin tubes that connect to the bladder. The urine is pushed through the ureters by peristalsis, where the muscles in the ureter walls contract and relax in a wave-like fashion. Urine is deposited into the bladder in small amounts, every 10 to 15 seconds.
Holding Urine
The bladder is a hollow organ that expands as it fills with urine and shrinks after emptying. The main muscle in the bladder wall, called the detrusor muscle, relaxes to allow the bladder to fill. Circular muscles, known as sphincters, close tightly around the bladder opening and prevent urine from leaking out of the body. The National Kidney and Urologic Diseases Information Clearing House, or NKUDIC, estimates that a normal bladder can hold up to 16 ounces of urine comfortably for two to five hours. Exact bladder capacity and duration of holding vary by the individual.
Voiding
Voiding is another word to describe urinating or emptying the bladder. As the bladder fills, receptors in the bladder send signals to the brain, and this elicits the urge to urinate. The urge intensifies as the bladder reaches capacity. When it is time to urinate, the brain instructs the detrusor muscle to tighten while the sphincter muscles relax, so the urine exits the bladder, travels through the urethra and exits the body. The Australian Government Department of Health and Aging states that voiding usually occurs four to eight times a day. The NKUDIC adds that adults eliminate about a quart and a half of urine each day, and certain pharmaceutical drugs can increase this amount.
Pathology
When something goes awry in the urinary process, urinary discomfort may arise. MedlinePlus, a service of the National Institutes of Health, states that the most common bladder abnormalities are infection, incontinence, interstitial cystitis and bladder cancer. Bladder infection, or cystitis, occurs when bacteria travel up the ureter and infect the bladder, which is normally sterile. Incontinence is a loss of urinary control due to weakened sphincter muscles. Interstitial cystitis is a chronic disorder where the bladder wall becomes inflamed, leading to frequent and painful urination. Bladder cancer occurs in the bladder lining and is a relatively common cancer in the United States. Any suggestion of urinary tract abnormality should be evaluated and treated by a qualified health care professional.
